1. Field of the Invention
This invention relates to vehicles having multiple power sources to achieve improved fuel-efficiency for cruising without decrease in performance in acceleration and hill-climbing.
2. Description of the Prior Art
Increased global demand for vehicular fuel without corresponding increase in available fuel supply has resulted in rising gas prices and the development of vehicles with improved fuel efficiency such as hybrid vehicles which use an internal combustion engine and an electric motor adapted to augment the output of the internal combustion engine when more power is needed. Rechargeable storage batteries on the vehicle energize the electric motor.
Hybrid vehicles are complex and expensive to manufacture and maintain due to the need for high amperage capacity batteries and associated control components. One particular disadvantage of hybrid vehicles is that, when the charge of the batteries is exhausted, such as during prolonged uphill climbs, the vehicle suddenly becomes severely under-powered because the electric motor is then unable to supply the needed additional power, and the vehicle has to rely solely on the power supplied by its down-sized engine. Means to solve this problem by reducing or eliminating such dependence on expensive high-capacity batteries would be greatly desirable.
It is well known that by simply using a small displacement internal combustion engine in a vehicle instead of its standard engine, the vehicle will gain improved fuel efficiency, but will have poor acceleration performance. The literature states that a standard sedan can be maintained at a cruising speed of 55 MPH using about 8 to 15 horsepower of engine output. The market, however, requires that the vehicle can accelerate from 0 to 60 MPH within 10 to 12 seconds, otherwise the vehicle will not sell. To be marketable, it would need additional power to improve acceleration. For instance a vehicle weighing 2950 lbs. will need about 120 HP to accelerate from zero to 60 MPH within 12 seconds.
Other proposed techniques for improving fuel efficiency include use of non-hybrid vehicles having two or more engines. So far, however, this approach has not had significant success in the market mainly due to difficulties in achieving optimum coordination of the engines.
Another earlier fuel-saving approach involves means for deactivating some cylinders in a regular internal combustion engine for economical operation when less power is needed, such as when cruising on a level highway, and reactivating them when more power is needed, such as when accelerating or climbing a grade. Fuel savings through this solution, however, has been severely limited, mainly due to power losses associated with the continuing reciprocating motion of the components (pistons, con rods, etc.) within the deactivated cylinders. Means to eliminate such power loss is included in the present invention.
A review of the prior art illustrates further shortcomings in providing solutions to the aforesaid problems.
U.S. Pat. No. 6,179,098 to Belloso discloses a fuel-efficient and inexpensive automobile having two engines, each coupled to a drive wheel by way of a continuously variable ratio torque converter. Both engines are used for acceleration or hill-climbing. Either engine is then used for economical cruising. One disadvantage of this system is the limited power capacity and speed range of current continuously variable ratio torque converters.
U.S. Pat. No. 6,637,283 to Belloso discloses a Control Apparatus for a Continuously Variable Transmission (CVT) which increases its operational speed range, adds reverse functionality and provides means for it to accommodate two separate power sources. However, it does not improve power handling capacity.
U.S. Pat. No. 4,439,989 to Yamakawa discloses a system wherein two or more engine units are each coupled to a transmission through an electromagnetic power clutch. The system includes means for operating the engines at a proper phase difference of, preferably 180 degrees to prevent unwanted vibrations. This system is complex and is not readily adaptable for use in automotive vehicles, particularly for the specific purpose of improving fuel efficiency.
Other disclosures of wheeled vehicles employing multiple engines or motors are found in U.S. Pat. Nos. 4,481,841; 4,306,630; 4,475,611; 5,253,724; and 5,429,543.
U.S. Pat. No. 2,462,902 to Rockwell, et. al., discloses a vehicle with a main engine that drives the rear axle and a booster engine that drives the front axle. The main engine is associated with a power train having a clutch, speed change transmission, propeller shaft, two-speed rear axle drive gear, and a differential. The booster engine has a power train consisting of a clutch, speed change transmission, propeller shaft, disengageable rear drive, and differential. Although the dual engines of Rockwell, et. al., provide some versatility of operation, particularly when the main engine is overloaded and requires the added power of the booster engine, the several required power train components increase the cost and weight of the vehicle, and do not necessarily improve fuel efficiency.
U.S. Pat. No. 4,697,660 to Wu, et. al., discloses a vehicle powered by an internal combustion engine and an electric motor. A torque converter is disposed between the output shafts of the engine and motor. A transmission is disposed on the output shaft of the motor adjacent to a solenoid clutch. The vehicle may be powered by the engine or the motor, or by both for increased power. Electricity to energize the motor is supplied by rechargeable batteries causing the motor to be unable to provide power when the batteries are discharged during heavy duty operations. This patent does not eliminate the need for high-capacity batteries, and it does not teach use of more than one internal combustion engine in the vehicle.
U.S. Pat. No. 6,594,998 to Bogucki discloses a system combining independent, initially separate internal combustion engines wherein engines not immediately required for power are shut down and disconnected from the running engine(s) and drive train, to reduce fuel consumption. A microprocessor determines vehicle power requirements from engine sensors, and hydraulic pistons controlled by the microprocessor bring the engine units into and out of engagement with each other. Friction plates and locking pins are provided for coupling the crankshafts at predetermined relative angular positions. The need to bring the crankshafts to predetermined angular positions relative to each other so that locking pins can be used to couple the crankshafts to each other makes this system extremely complicated and prone to failure. This is further complicated by engine mount modifications to permit some engine units to be moved closer to other engine units for engagement and away from said units for disengagement, thereby increasing further the chances of failure.
U.S. Pat. No. 6,878,092 to Schustek, et. al., discloses a drive arrangement for at least one auxiliary system of a vehicle having an internal combustion engine. It provides at least one supplementary motor and a planetary gear operative between the engine and motor. The auxiliary system may be a climate control compressor. Such arrangement does not provide power to propel the vehicle, and is not useful for improving the overall fuel efficiency of the vehicle.
None of the aforesaid disclosures provide a simple and cost-effective way to improve the fuel efficiency of automotive vehicles, particularly for long distance travel on the highways. As previously discussed, the hybrid system has proved complex and expensive, especially because it requires high-capacity, high voltage batteries.
It is accordingly a primary object of this invention to provide means for improving the fuel efficiency of automotive vehicles without the need for high-capacity batteries.
It is a specific object of the present invention to use power generated by an on-board auxiliary accelerator engine for acceleration and hill-climbing, etc., instead of relying on power stored in high-capacity batteries.
It is another object of this invention to provide simple, automatic and reliable means for combining the power of said auxiliary accelerator engine with the power of a primary cruiser engine for acceleration and hill-climbing, etc., and then selectively using the power of said primary engine for economical long distance cruising on the highway.
It is also an object of the present invention to use off-the-shelf coupling means of proven reliability to couple said accelerator engine with said primary engine for increased vehicle power, and to decouple said engines for traveling economically based upon said primary engine.
It is a further object of this invention to provide add-on modification means for improving the fuel efficiency of existing motor vehicles.
It is an additional object of the present invention to provide means to modify an existing motor vehicle into an improved hybrid vehicle that does not require the use of expensive high-capacity batteries.
These objects and other objects and advantages of the invention will be apparent from the following description.